// SPDX-License-Identifier: GPL-2.0-or-later
/* Peer event handling, typically ICMP messages.
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include "ar-internal.h"
static void rxrpc_store_error(struct rxrpc_peer *, struct sk_buff *);
static void rxrpc_distribute_error(struct rxrpc_peer *, struct sk_buff *,
enum rxrpc_call_completion, int);
/*
* Find the peer associated with a local error.
*/
static struct rxrpc_peer *rxrpc_lookup_peer_local_rcu(struct rxrpc_local *local,
const struct sk_buff *skb,
struct sockaddr_rxrpc *srx)
{
struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
_enter("");
memset(srx, 0, sizeof(*srx));
srx->transport_type = local->srx.transport_type;
srx->transport_len = local->srx.transport_len;
srx->transport.family = local->srx.transport.family;
/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
* versa?
*/
switch (srx->transport.family) {
case AF_INET:
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.family = AF_INET;
srx->transport.sin.sin_port = serr->port;
switch (serr->ee.ee_origin) {
case SO_EE_ORIGIN_ICMP:
memcpy(&srx->transport.sin.sin_addr,
skb_network_header(skb) + serr->addr_offset,
sizeof(struct in_addr));
break;
case SO_EE_ORIGIN_ICMP6:
memcpy(&srx->transport.sin.sin_addr,
skb_network_header(skb) + serr->addr_offset + 12,
sizeof(struct in_addr));
break;
default:
memcpy(&srx->transport.sin.sin_addr, &ip_hdr(skb)->saddr,
sizeof(struct in_addr));
break;
}
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
switch (serr->ee.ee_origin) {
case SO_EE_ORIGIN_ICMP6:
srx->transport.sin6.sin6_port = serr->port;
memcpy(&srx->transport.sin6.sin6_addr,
skb_network_header(skb) + serr->addr_offset,
sizeof(struct in6_addr));
break;
case SO_EE_ORIGIN_ICMP:
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.family = AF_INET;
srx->transport.sin.sin_port = serr->port;
memcpy(&srx->transport.sin.sin_addr,
skb_network_header(skb) + serr->addr_offset,
sizeof(struct in_addr));
break;
default:
memcpy(&srx->transport.sin6.sin6_addr,
&ipv6_hdr(skb)->saddr,
sizeof(struct in6_addr));
break;
}
break;
#endif
default:
BUG();
}
return rxrpc_lookup_peer_rcu(local, srx);
}
/*
* Handle an MTU/fragmentation problem.
*/
static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, unsigned int mtu)
{
/* wind down the local interface MTU */
if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu)
peer->if_mtu = mtu;
if (mtu == 0) {
/* they didn't give us a size, estimate one */
mtu = peer->if_mtu;
if (mtu > 1500) {
mtu >>= 1;
if (mtu < 1500)
mtu = 1500;
} else {
mtu -= 100;
if (mtu < peer->hdrsize)
mtu = peer->hdrsize + 4;
}
}
if (mtu < peer->mtu) {
spin_lock(&peer->lock);
peer->mtu = mtu;
peer->maxdata = peer->mtu - peer->hdrsize;
spin_unlock(&peer->lock);
}
}
/*
* Handle an error received on the local endpoint.
*/
void rxrpc_input_error(struct rxrpc_local *local, struct sk_buff *skb)
{
struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
struct sockaddr_rxrpc srx;
struct rxrpc_peer *peer = NULL;
_enter("L=%x", local->debug_id);
if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
_leave("UDP empty message");
return;
}
rcu_read_lock();
peer = rxrpc_lookup_peer_local_rcu(local, skb, &srx);
if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_input_error))
peer = NULL;
rcu_read_unlock();
if (!peer)
return;
trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
serr->ee.ee_type == ICMP_DEST_UNREACH &&
serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
rxrpc_adjust_mtu(peer, serr->ee.ee_info);
goto out;
}
rxrpc_store_error(peer, skb);
out:
rxrpc_put_peer(peer, rxrpc_peer_put_input_error);
}
/*
* Map an error report to error codes on the peer record.
*/
static void rxrpc_store_error(struct rxrpc_peer *peer, struct sk_buff *skb)
{
enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
struct sock_extended_err *ee = &serr->ee;
int err = ee->ee_errno;
_enter("");
switch (ee->ee_origin) {
case SO_EE_ORIGIN_NONE:
case SO_EE_ORIGIN_LOCAL:
compl = RXRPC_CALL_LOCAL_ERROR;
break;
case SO_EE_ORIGIN_ICMP6:
if (err == EACCES)
err = EHOSTUNREACH;
fallthrough;
case SO_EE_ORIGIN_ICMP:
default:
break;
}
rxrpc_distribute_error(peer, skb, compl, err);
}
/*
* Distribute an error that occurred on a peer.
*/
static void rxrpc_distribute_error(struct rxrpc_peer *peer, struct sk_buff *skb,
enum rxrpc_call_completion compl, int err)
{
struct rxrpc_call *call;
HLIST_HEAD(error_targets);
spin_lock(&peer->lock);
hlist_move_list(&peer->error_targets, &error_targets);
while (!hlist_empty(&error_targets)) {
call = hlist_entry(error_targets.first,
struct rxrpc_call, error_link);
hlist_del_init(&call->error_link);
spin_unlock(&peer->lock);
rxrpc_see_call(call, rxrpc_call_see_distribute_error);
rxrpc_set_call_completion(call, compl, 0, -err);
rxrpc_input_call_event(call, skb);
spin_lock(&peer->lock);
}
spin_unlock(&peer->lock);
}
/*
* Perform keep-alive pings.
*/
static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
struct list_head *collector,
time64_t base,
u8 cursor)
{
struct rxrpc_peer *peer;
const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
time64_t keepalive_at;
bool use;
int slot;
spin_lock(&rxnet->peer_hash_lock);
while (!list_empty(collector)) {
peer = list_entry(collector->next,
struct rxrpc_peer, keepalive_link);
list_del_init(&peer->keepalive_link);
if (!rxrpc_get_peer_maybe(peer, rxrpc_peer_get_keepalive))
continue;
use = __rxrpc_use_local(peer->local, rxrpc_local_use_peer_keepalive);
spin_unlock(&rxnet->peer_hash_lock);
if (use) {
keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
slot = keepalive_at - base;
_debug("%02x peer %u t=%d {%pISp}",
cursor, peer->debug_id, slot, &peer->srx.transport);
if (keepalive_at <= base ||
keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
rxrpc_send_keepalive(peer);
slot = RXRPC_KEEPALIVE_TIME;
}
/* A transmission to this peer occurred since last we
* examined it so put it into the appropriate future
* bucket.
*/
slot += cursor;
slot &= mask;
spin_lock(&rxnet->peer_hash_lock);
list_add_tail(&peer->keepalive_link,
&rxnet->peer_keepalive[slot & mask]);
spin_unlock(&rxnet->peer_hash_lock);
rxrpc_unuse_local(peer->local, rxrpc_local_unuse_peer_keepalive);
}
rxrpc_put_peer(peer, rxrpc_peer_put_keepalive);
spin_lock(&rxnet->peer_hash_lock);
}
spin_unlock(&rxnet->peer_hash_lock);
}
/*
* Perform keep-alive pings with VERSION packets to keep any NAT alive.
*/
void rxrpc_peer_keepalive_worker(struct work_struct *work)
{
struct rxrpc_net *rxnet =
container_of(work, struct rxrpc_net, peer_keepalive_work);
const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
time64_t base, now, delay;
u8 cursor, stop;
LIST_HEAD(collector);
now = ktime_get_seconds();
base = rxnet->peer_keepalive_base;
cursor = rxnet->peer_keepalive_cursor;
_enter("%lld,%u", base - now, cursor);
if (!rxnet->live)
return;
/* Remove to a temporary list all the peers that are currently lodged
* in expired buckets plus all new peers.
*
* Everything in the bucket at the cursor is processed this
* second; the bucket at cursor + 1 goes at now + 1s and so
* on...
*/
spin_lock(&rxnet->peer_hash_lock);
list_splice_init(&rxnet->peer_keepalive_new, &collector);
stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
while (base <= now && (s8)(cursor - stop) < 0) {
list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
&collector);
base++;
cursor++;
}
base = now;
spin_unlock(&rxnet->peer_hash_lock);
rxnet->peer_keepalive_base = base;
rxnet->peer_keepalive_cursor = cursor;
rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
ASSERT(list_empty(&collector));
/* Schedule the timer for the next occupied timeslot. */
cursor = rxnet->peer_keepalive_cursor;
stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
for (; (s8)(cursor - stop) < 0; cursor++) {
if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
break;
base++;
}
now = ktime_get_seconds();
delay = base - now;
if (delay < 1)
delay = 1;
delay *= HZ;
if (rxnet->live)
timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
_leave("");
}
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